This invention relates to a tractor with a PTO apparatus having a rear PTO shaft disposed at the rear of a vehicle body and a mid-PTO shaft disposed under the vehicle body.
A known tractor includes a rear PTO shaft disposed at the rear of a vehicle body, a mid-PTO shaft disposed under the vehicle body, and a PTO mode selecting mechanism for selecting an output state from three output states. The three output states are a state of outputting power only from the rear PTO shaft, a state of outputting power from both the rear PTO shaft and mid-PTO shaft, and a state of outputting power only from the mid-PTO shaft. The tractor further includes a PTO clutch disposed on a power transmission line upstream of the PTO mode selecting mechanism (see Japanese Application “Kokai” No. 5-162551, FIG. 7, for example).
The above PTO transmission structure has excellent practical utility for enabling a wide range of operations using the rear PTO shaft and mid-PTO shaft. However, the PTO mode selecting mechanism could be operated inadvertently without disengaging the PTO clutch, thereby abruptly rotating the PTO shafts from stationary state, or abruptly stopping the PTO shafts in rotation. In this way, an excessive force may be applied to meshed gears or splines on the PTO transmission line to damage such components or produce a loud noise.